This program project will consist of five distinct but interrelated research projects which will investigate various aspects of the epidemiology of sand fly-borne diseases in Columbia. Primary emphasis will be on leishmaniasis, with secondary interest in arboviruses transmitted by phlebotomine sand flies. The project will involve the disciplines of parasitology, medical entomology, pathology, virology, epidemiology, biochemistry and genetics. Most of the work on this project will be done in South America in collaboration with scientists at the Instituto Nacional de Salud and the Colombian Ministry of Health. Project 1 will identify the specific parasites causing human leishmaniasis in Columbia and will attempt to classify the clinical manifestations, histopathology and prognosis associated with each of these agents. Project 2 will study the biology and vector potential of the major anthropophilic sand flies of Colombia. It will also identify the Leishmania and arboviruses associated with each of these insect species. Project 3 will determine the animal reservoirs of human pathogenic Leishmania in the country. Project 4 will be a biochemical and genetic study of Colombian Leishmania and their sand fly vectors. Leishmania isolates from humans, sand flies and animals in Projects 1, 2 and 3, respectively, will be characterized by enzyme electrophoresis. Genetic studies of natural sand fly populations will also be done using the same electrophoretic techniques. Project 5 will identify the arboviruses associated with sand flies in Columbia and will evaluate their public health importance. The duration of the proposed program project is five years.